Scanning and Defocusing Characteristics of Microstrip Reflectarrays

Results of an investigation on beam scanning by lateral displacement of the feed of a microstrip reflectarray are presented. Radiation pattern characteristics such as gain loss and sidelobe level degradation as a function of scan angle are discussed for different reflectarray geometries. Scanning of reflectarrays is limited to a few beamwidths, and their radiation pattern performance is found to be poorer than that of a comparable parabolic reflector antenna.